This invention relates to an apparatus for smoking and more particularly to pipes having a liquid filtering agent.
There are many types of pipes in the prior art which have a pipe bowl, a liquid filtering agent in a closed reservoir, a smoke tube extending from the pipe bowl to a point in the reservoir and below the top surface of the filtering agent, and a stem extending from a point in the reservoir and above the top surface of the filtering agent to the user. In operation, smoke passes from the bowl through the smoke tube, through a portion of the filtering agent, through a portion of the reservoir above the top surface of the filtering agent, and through the stem to the user. The advantages of such pipes are well known, and include removal of toxic substances from the smoke and cooling of the smoke. However, the prior art pipes generally suffer from the problem of leakage of the liquid filtering agent from the reservoir into either the smoke tube or the stem, or both, while the pipe is oriented in positions other than its normal upright position. This problem of leakage under various pipe orientations is of particular concern in compact, portable pipes which are intended to be easily carried about by the smoker when not in use. Non-upright orientation and subsequent leakage may also occur when the pipe bowl is being emptied of ashes or otherwise cleaned, or when tobacco is being added to the bowl by scooping into a tobacco pouch.
There have been some attempts to the solution of this leakage problem. One approach to this problem is described in the present applicant's U.S. Pat. No. 4,036,240 which discloses a pipe having a leak resistant filter cartridge with a dual concentric smoke tube arrangement protruding into the reservoir. The geometry of the tubes is selected with respect to the volume of liquid placed within the cartridge to minimize leakage. However, it is possible that under certain conditions, e.g. due to splashing, some of the filtering agent may enter the smoke tubes and escape from the reservoir.
Another prior art approach to this leakage problem utilizes gravitationally controlled ball valves as disclosed in U.S. Pat. No. 3,315,687 wherein these gravity valves are intended to prevent leakage from both the smoke tube and the stem. In actual use, this approach is not practical because, if the smoking apparatus is of reasonable size, the gravity controlled balls are necessarily of relatively low mass which results in very low forces acting on them. These low forces produce very unreliable sealing at the valves under normal usage conditions. In addition, because the balls are located in the smoke path, they quickly become coated with sticky smoke condensates which soon prevent motion of the balls.
It is the object of the present invention to provide a portable smoking apparatus having a liquid filtering agent in a reservoir, wherein the apparatus can be made more compact and substantially immune to leakage of the filtering agent while being transported, or being filled with tobacco, or being emptied of ashes, regardless of its orientation.